Conventional laser energy detectors are typically thermal, pyroelectric or photodiode based.
Thermal type laser energy meters are accurate but can only measure laser pulses approximately every 5 seconds, because of their inherent slow response. They are unsuitable, therefore, for measuring pulsing laser radiation having a pulse rate faster than one pulse every 5 seconds.
Pyroelectric detectors can measure pulses that occur at a much more rapid rate, but, as known in the art, are generally inaccurate, typically having an accuracy of about .+-.5%. In addition, they do not have absolute calibration, nor can they be used for high energy density pulses. A further disadvantage of pyroelectric detectors is that they are also sensitive to humidity and to microphonics.
Photodiode detectors are generally employed to sample scattered radiation. Typically, they have an accuracy of about .+-.10%.
U.S. Pat. Nos. 3,344,703, 3,464,267, 3,535,523, 3,575,048, 3,687,558, 4,019,381, 4,035,088, 4,037,470, 4,130,363, 4,187,026, 4,321,824, 4,381,148, 4,413,916, 4,431,306, 4,522,511, 4,596,461, 4,728,188, 4,737,643, 4,765,749, 4,797,555, 4,828,384 and 4,842,404 describe various devices for measuring radiation.